Absorbent articles, such as baby diapers, training pants, adult incontinence products and other such absorbent products include a topsheet that is closest to the wearer, an outer, moisture-impermeable backsheet, and an absorbent core. Disposable absorbent products have met with widespread acceptance in the marketplace for a variety of applications, including infant and adult incontinence care, in view of the manner in which such products can provide effective and convenient liquid absorption and retention while maintaining the comfort of the wearer. Softness and ability to provide comfort while product is being worn by a wearer is paramount to the acceptance of the product. Perception of the softness by a user or caregiver taking the product out of its packaging is equally important. If a caregiver or user senses the hard spots and superabsorbent polymer (SAP) particles through the outer cover, could lead to negative perception of the product and its efficacy.
Softness of the nonwoven backsheet depends on visual, auditory, and tactile signals. The tactile softness signal is perceived most during use and when the product is first touched by the user. The tactile signal of absorbent articles is mostly perceived via an outer cover that has the nonwoven backsheet and topsheet. The tactile softness signal exhibited by the outer cover depends on the flexibility of nonwoven fibers, pliability, surface friction characteristics, loose fibers or free fiber ends, amount of fibers, and the cushiness of these elements.
Significant efforts have been made to improve the tactile signals when handling absorbent products. Conventional means of improving tactile signals include embossing with soft calender patterns, an increase in basis weight, increase in fiber density to increase loft, alterations in resin chemistry, adding soft additives, slip agents, bi-component fiber technology, hydro entangling, and hydro engorging. These approaches are unfavorable because they drive up raw material costs. Yet another limitation is that soft calendar patterns, bi-component fiber nonwoven, additives, spin finishes, and slip agents all have an adverse effect of decreasing mechanical properties, such as tensile strength, of the absorbent article.
Prior methods of providing a soft back sheet and poly film laminate outercover include the multiple limitations. First, there is a constant desire to run production lines faster in order to reduce manufacturing costs. However, when production line speeds increase, a probability of having uneven regions per unit area in an absorbent core of the product also increases. When these uneven regions are compressed for packaging, hard spots are formed. Hard spots may appear more pronounced in particular when using relatively high production speeds and for relatively thin absorbent cores.
Secondly, there is constant desire to go towards thinner and thinner outercover laminates to achieve desired cost structure. The relatively thin backsheet and poly films allow for hard spots and SAP particles to protrude and poke easily through the poly film/backsheet laminate.
Furthermore, there is a trend towards thinner absorbent products has been driven by a desire for absorbent products to take up less space for transport and storage. Thus, absorbent products are packaged by compressing the absorbent product between compression rolls to reduce its thickness. This increased compression levels can lead to hard spots that protrude and poke through the poly film/backsheet laminate, thereby adversely affecting the softness signal. Another limitation is that a reduction in the compression in package and/or increasing the package size will adversely affect the cost strategy.
Hard-spots can be felt by a user are caregiver of the absorbent product both before use, e.g., taking product out of bags, and in use. Being relatively stiff, the hard-spots may be perceived by a user as causing a less comfortable and less efficient product. These hard spots felt by user could lead to significant negative impact on the overall softness and comfort in case of bed pads and adult incontinent products and can lead to bed sore and rashes.